IAAF chief Sebastian Coe says Russia has shown "significant change" in its attitude to tackling its doping scandal but refused to set a deadline for the nation's return to world athletics.
Russia has been banned from international athletics competition since November 2015 over doping concerns while its anti-doping agency, RUSADA, is also yet to be declared fully compliant by the World Anti-Doping Agency.
In a separate development, Russian athletes have effectively been banned from next year's Winter Olympics in Pyeongchang unless they can satisfy stringent drug-testing regulations in order to compete as neutrals.
While Coe indicated that he saw reasons for optimism in recent developments within Russia, he cautioned that the IAAF would still resist setting any prospective timeframe for the nation's reintegration.
"We made a decision that in a way was quite different to the one the IOC (International Olympic Committee) was confronted with," Coe told the BBC.
"I've had 149 or 150 positive tests in the sport, from Russia within a three or four-year period - it was very clear as far I was concerned and the Council of the IAAF was concerned that nobody else was going to come to our rescue here. We had to take the appropriate action.
"We set up the task force which created the five-step criteria by which they would be judged - and actually they're moving in the right direction and we've got some significant change.
"I am faithful to the independent work of the task force and the task force will recommend to the council when that moment (of reintegration) is."
Despite the IOC's decision to sanction Russia ahead of Pyeongchang 2018, a number of winter sports governing bodies appear reluctant to follow the IAAF's example.
Some skeleton and bobsleigh athletes banned for life by the IOC in the wake of the Oswald Commission report in doping are still competing on their respective World Cup circuits.
One of them, Russian skeleton racer Elena Nikitina, who has been stripped of the bronze medal she won at Sochi 2014, won the World Cup and European Championship in Winterberg on Saturday.
